In this Learnable video you’ll learn about variable scope in JavaScript. How, when, and where you declare a variable dictates how you can access that variable later in your code. We’ll also see how understanding variable scope leads on to the extremely powerful concept of closures.
在这个视频中, 您将了解JavaScript的变量作用域(variable scope)。声明一个变量的位置，方式和时机（ How, when, and where）决定了在其他地方是否能看见此变量。视频中还将看到如何理解变量范围并了解非常强大的闭包(closures)概念。
视频链接地址: https://www.youtube.com/watch?v=iSlSxDNarDY
原文链接: http://www.sitepoint.com/understanding-variable-scope-closures-without-losing-mind/
作者: 铁锚 http://blog.csdn.net/renfufei
日期: 2015年07月14日